Factors affecting outcomes of corneal collagen crosslinking treatment.

Purpose: To assess the effects of preoperative patient characteristics on clinical outcomes of corneal crosslinking (CXL) treatment in patients with progressive keratoconus.

Methods: This retrospective study comprised 96 eyes of 96 patients who had unilateral CXL treatment for progressive keratoconus. All patients underwent a complete ophthalmological examination and corneal topography at baseline and 1 year. Subgroup analyses were performed according to the age (<30 and ≥ 30 years), gender, preoperative corrected distance visual acuity (CDVA, <0.3 and ≥ 0.3 logMAR (log of the minimum angle of resolution)), preoperative maximum keratometry (K, <54 and ≥ 54 D), baseline topographic cone location (central, paracentral, and peripheral), and preoperative thinnest pachymetry (<450 and ≥ 450 μm) to determine the associations between preoperative patient characteristics and outcomes (changes in visual acuity and maximum keratometry) of CXL treatment.

Results: In the entire study population, mean CDVA and maximum K significantly improved after CXL treatment (P<0.001). Patients with a preoperative CDVA of 20/40 Snellen equivalent or worse (≥ 0.3 logMAR) experienced more visual improvement after CXL treatment (P<0.001). However, an age ≥ 30 years and a baseline thinnest pachymetry less than 450 μm were found significantly associated with more flattening in maximum keratometry (P=0.024, P=0.005 respectively). Gender, preoperative maximum K, and baseline topographic cone location did not show significant effect on postoperative visual acuity and maximum keratometry (P>0.05).

Conclusions: In patients with progressive keratoconus, age, baseline visual acuity, and baseline thinnest pachymetry seem to affect the success of the CXL treatment.